1. Field of Invention
The present invention relates to a wrist-fit type communication device having the function of receiving and transmitting communication radio waves. More particularly, the present invention relates to a clasp structure of two wrist bands which are integrated with two antenna sheets, respectively, for forming a loop-like antenna when fitted to a wrist.
2. Description of Related Art
As portable transmitters or receivers, wristwatches with FM radios and wristwatch-type individual select call receivers have been known. In these portable communication devices, a wristwatch-type wrist-fitting communication device includes, as shown in FIG. 15(A), a device main body 2C containing communication circuits; a first wrist band 3C covering a first antenna plate 30C, extending from the 6 o'clock side of a wristwatch of the device main body 2C, with a flexible insulating material; and a second wrist band 4C covering a second antenna plate 40C, extending from the 12 o'clock side, with a flexible insulating material. In addition, a clasp metal fitting main body 5C electrically connected to the first antenna plate 30C, and clasping hook metal fitting 6C are fixed to the end portion of the first wrist band 3C and a predetermined position of the second wrist band 4C, respectively, as shown in FIGS. 15 (B) and 15(C). When the first wrist band 3C and the second wrist band 4C are clasped, the first antenna plate 30C and the second antenna plate 40C are electrically connected by these metal fittings.
Since the described clasp device is widely adopted for common watches, a detailed description thereof will be omitted. When the hook metal fitting 6C is rotated around the axis of a connecting shaft 62C so that it is overlapped onto the clasp metal fitting main body 5C, after a hooking portion 61C of the hook metal fitting 6C has been hooked on one engagement shaft 51C of two engaging shafts included in the clasp metal fitting main body 5C, a catch portion 63C of the hook metal fitting 6C catches the other engagement shaft 52C of the clasp metal fitting main body 5C while it is elastically deformed, so that the first wrist band 3C and the second wrist band 4C are clasped.
As a result, the first antenna plate 30C is electrically connected to the second antenna plate 40C through the connecting shaft 62C, the hook metal fitting 6C, the catch portion 63C, the engagement shaft 52C, and the clasp metal fitting main body 5C. In addition, if a presser plate 54C supported by the engagement shaft 53C on the side of the clasp metal fitting main body 5C is raised, the clasp metal fitting main body 5C can be slid on the first wrist band 3C, so that the length of the band can be adjusted to the circumference of a user's wrist. At this time, since recessed portions 301C are formed on the inner peripheral surface in the longitudinal direction of the first wrist band 3C where the first antenna plate 30C is bare at predetermined intervals, if the clasp metal fitting main body 5C is shifted to the position where positioning projections 55C of the clasp metal fitting main body 5C are fitted to any of these recessed portions 301C and thereafter, and the presser plate 54C is folded, the clasp metal fitting main body 5C is returned to a state where it is fixed to the first wrist band 3C because a band presser pawl (not shown) is formed on the presser plate 54C. In this state, the positioning projections 55C are electrically connected to the first antenna plate 30C in the recessed portions 301C, so that the first antenna plate 30C and the clasp metal fitting main body 5C are electrically connected.
However, although the conventional wrist-fit-type communication device is of a type in which two separate wrist bands are connected through the clasp metal fitting main body 5C and the hook metal fitting 6C, the first antenna plate 30C and the second antenna plate 40C are integrated with the first wrist band 3C and the second wrist band 4C, respectively, and these antenna plates are covered with thick synthetic resin so as not to injure a user's wrist. Thus, the first wrist band 3C and the second wrist band 4C have poor flexibility compared with bands included in common wristwatches. For this reason, when the second wrist band 4C is to be drawn after the device main body 2C has been placed on the wrist and the first wrist band 3C has been wound around the wrist, the second wrist band 4C does not hang over the wrist but remains extended horizontally, so that the user's fingers cannot easily reach the second wrist band 4C, whereby the problem of poor fitting to the wrist is encountered.
In consideration of the problems described above, an object of the present invention is to provide a wrist-fit-type communication device including two antenna plates integrated with the wrist band, respectively, wherein the fitting property to a wrist can be improved.
In addition, an object of the present invention is to provide a wrist-fit-type communication device including a contact mechanism capable of electrically connecting the two antenna plates with certainty even when the fitting to the wrist is improved.